org.springframework.binding.value.support
Class DefaultValueChangeDetector

java.lang.Object
  org.springframework.binding.value.support.DefaultValueChangeDetector

All Implemented Interfaces:

ValueChangeDetector

public class DefaultValueChangeDetector
extends Object
implements ValueChangeDetector

Implementation of ValueChangeDetector that maintains a set of classes for which it is "safe" to use equals() for detecting a change in value (those classes that have immutable values). For all objects of a type in this set, the value comparison will be done using equals. For all other types, object equivalence (the == operator) will be used.

This is the default value change detector handed out by the Application Services.

Author:

Larry Streepy

Field Summary

protected Set

classesWithSafeEquals

Constructor Summary

DefaultValueChangeDetector()

Method Summary

Collection	getClassesWithSafeEquals() Get the set of classes that have an equals method that is safe to use for determining a value change.
boolean	hasValueChanged(Object oldValue, Object newValue) Determines if there has been a change in value between the provided arguments.
void	setClassesWithSafeEquals(Collection classes) Specify the set of classes that have an equals method that is safe to use for determining a value change.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

classesWithSafeEquals

protected final Set classesWithSafeEquals

Constructor Detail

DefaultValueChangeDetector

public DefaultValueChangeDetector()

Method Detail

hasValueChanged

public boolean hasValueChanged(Object oldValue,
                               Object newValue)

Determines if there has been a change in value between the provided arguments. As many objects do not implement #equals in a manner that is strict enough for the requirements of this class, difference is determined using !=, however, to improve accuracy #equals will be used when this is definitely safe e.g. for Strings, Booleans, Numbers, Dates.

Specified by:

hasValueChanged in interface ValueChangeDetector

Parameters:

oldValue - Original object value

newValue - New object value

Returns:

true if the objects are different enough to indicate a change in the value model

setClassesWithSafeEquals

public void setClassesWithSafeEquals(Collection classes)

Specify the set of classes that have an equals method that is safe to use for determining a value change.

Parameters:

classes - with safe equals methods

getClassesWithSafeEquals

public Collection getClassesWithSafeEquals()

Get the set of classes that have an equals method that is safe to use for determining a value change.

Returns:

Collection of classes with safe equals methods